SPF, DKIM, DMARC authentication

When you send an email from ActiveCampaign, the recipient's ISP (such as Gmail, Yahoo, AOL or Outlook) will use a variety of methods to determine if you are permitted to send communications using your "From" email address. For example, you are not permitted to send an email with the from email address info@example.com unless you own Example.com. If someone sends messages posing as Example.com, ISPs have methods of identifying this as phishing and will block it.

SPF, DKIM, and DMARC are the three established methods used to verify a sender's identity. ActiveCampaign does not require that you do anything to set these up, because we've already covered it for you. However, there are circumstances when it can be beneficial to set these identifiers up on your domain.

The most common reasons for setting up your own authentication are:

  • To remove the “via...” header from Gmail to enforce branding (see image below). A positive side effect of setting up DKIM is that this header disappears.
  • If your domain actually has a stronger reputation than ActiveCampaign's. This is rare because our domain has a long established reputation of sending good mail, but there are times when senders can benefit from relying more heavily on their own domain reputation.
  • If you want to enforce stricter security on your domain.

These methods of authentication should not be thought of as fixes for poor delivery. Simply setting up your own DKIM key, SPF, or DMARC will rarely, if ever, boost your delivery. If you have a poor sender reputation, authentication will not reverse or improve your reputation.

Authentication allows good senders to further solidify their reputation and protect their domain from bad senders who may try to hijack their domain.

As such, we make it easy for you to set up authentication, but you are not required to do so. 


DKIM is essentially a “signature” any sender can apply to their email messages. This signature makes clear that the purported sender of the message is actually the sender of the message. Any domain can be used as the “signature.” For example, a company called Example will sign their messages with the Example.com domain to confirm that the message was actually sent by Example.

This is accomplished by inserting a hidden, cryptographic signature into your email header (ActiveCampaign will do this) and then placing a public key on your website that verifies the authenticity of this signature.

All mail sent from ActiveCampaign will use ActiveCampaign's DKIM signature by default. ActiveCampaign's DKIM signature has a very good reputation. This is sufficient for most senders. However, it is easy to setup DKIM for your own domain if you want to.

To setup DKIM:

1. Click Settings in the left-side menu.

2. Click "Advanced."

3. Click the "I will manage my own email authentication" option.

4. Type your sending domain into the DKIM field and click the "Generate" button.

After you enter your domain, you will receive a record to add to your DNS at dk._domainkey.mydomain.com. Note that the values you generate here will not save on the page. They are just generated for use in setting up TXT records on your domain host.

You will need to add these TXT records to the DNS of your website. To find specific instructions for your host, we recommend searching Google for “add TXT record at _______." Fill in the blank with the name of your host (Godaddy, Hostgator, Cloudfare etc). 

After complete, you can use a tool like mail-tester.com to ensure that DKIM is working.


SPF records are public records on your website that authorize certain servers to send mail with your domain.

We actually handle SPF for all senders, because SPF protocol will check the sending server's domain for SPF, not your own domain.

As such, SPF is out of your hands. You don't need to setup SPF, even if you are using a Custom Domain.

Why should you set up SPF on your domain?

There is an older, deprecated version of SPF called SenderID where the recipient ISP checks the visible From Address for authentication. This means the "From" address domain you use to send the message (like @mydomain.com) would be checked for an SPF record that authorizes ActiveCampaign to send with this domain.

SenderID is deprecated and the only ISP of note that still checks for SenderID is Microsoft (this includes Outlook.com, Hotmail.com, Live.com, and MSN.com). There is no evidence that this check will influence your deliverability positively or negatively.

There may be other, smaller ISPs that still use some version of SenderID, although they are rare. And in some cases, it may be necessary to set up SPF/SenderID to ensure the notification emails from your automations deliver.

You can choose to add an SPF record to your domain to ensure your emails will pass a SenderID check. However, this will not have a noticeable effect on deliverability to any major ISP, since the standardized SPF check is handled by ActiveCampaign.

If you want to setup SenderID, follow these steps:

1. Click "Settings" in the left-side menu.

2. Click "Advanced."

3. Click the "I will manage my own email authentication" option.

4. Type your sending domain into the SenderID field.

5. Click "Generate."

If you already have an SPF record, it is important that you don't add a second.

Instead of having two SPF records, you should just add “include:emsd1.com” to the current SPF record, like this:

v=spf1 include:emsd1.com include:_spf.google.com ~all


DMARC builds on SPF and DKIM and tells ISPs like Gmail and Outlook what to do if your emails fail SPF or DKIM. ISPs will look to the DMARC record on your domain to know how they should handle mail that doesn't pass DMARC.

The lack of a DMARC record (which is the default) will tell ISPs to treat mail normally if it doesn't pass DMARC. A stricter DMARC policy will tell ISPs to reject or quarantine mail that doesn't pass a DMARC test.

DMARC is not a method to boost your deliverability. It permits you to enhance security for your domain.

By default, all domains will not have a DMARC record in place, and it is not necessary for you to set up a DMARC record for delivery. As such, DMARC is totally optional, and there is no immediate benefit to deliverability to setup DMARC, unless:

  1. Someone is actively spoofing your domain, sending fraudulent mail, and tarnishing your reputation. DMARC would let you identify this malicious activity and shut it down.
  2. You added a DMARC record that is “strict” which will lead ISPs to block mail that doesn't pass a DMARC test. A poorly configured DMARC is basically telling ISPs you want them to block your messages.

There are two options for DMARC: lenient and strict. We recommend setting up a lenient policy because this is the safest for deliverability. To set up a lenient DMARC policy, add this TXT record to your domain at _dmarc.mydomain.com:

v=DMARC1; p=none;

If you want to implement stronger security on your domain, you can set up a strict DMARC record that will tell ISPs to reject or quarantine mail that does not pass the DMARC test. To set up a strict DMARC record, we would advise you visit dmarc.org for recommendations to configure the record properly.

A strict record will require that you have a proper DKIM record setup for your sending domain, or else all your mail from ActiveCampaign will fail the DMARC test. Make sure you have set up DKIM for all of your sending domains before setting up a strict DMARC record. 

Additional Reading

In this article, we didn't attempt to explain the technical process of how SPF, DKIM, and DMARC work. Each of these authentication protocols has a public website where the technical specification is explained at depth:

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